Winter is coming, but the forecast hinges on looming La Ni?a

Current mild weather notwithstanding, winter is still coming – and a looming La Ni?a in the Pacific Ocean could impact the forecast for winter in 2024-25.

An official announcement that La Ni?a has formed could come as soon as mid-November, when federal forecasters give their monthly update on the climate pattern, which will play a major role in our winter weather.

A typical La Ni?a winter in the U.S. brings cold and snow to the Northwest and unusually dry conditions to most of the Southern states, according to the Climate Prediction Center. The Southeast and mid-Atlantic also tend to see higher-than-average temperatures during a La Ni?a winter.

The latest forecast from the Climate Prediction Center released earlier this month said there is a 60% chance that La Ni?a conditions will emerge by the end of November. And once it forms, it's expected to persist through January-March 2025. However, it’s likely to be a weak event.

What is La Ni?a?

La Ni?a is a natural climate pattern marked by cooler-than-average seawater in the central and eastern Pacific Ocean. When the water cools at least 0.9 degree Fahrenheit below average for three straight months, a La Ni?a is declared.

"While this may sound like a small change in temperature, it can cause significant changes in the weather patterns around the globe," AccuWeather meteorologist Brian Lada said.

It is one of the main drivers of weather in the United States, especially during the late fall, winter and early spring. It's the opposite to the more well-known El Ni?o, which occurs when Pacific Ocean water is at least 0.9 degree warmer than average for three months.

Mild, dry winter for many expected in 2024-2025

Federal forecasters last week said that, due to the likely La Ni?a, most of the USA's southern tier and the East Coast should see warmer-than-average temperatures this winter. In addition, most of the southern half of the USA – all the way from southern California to the Carolinas – should see less rain and snow than usual, which is potentially a concern for drought conditions.

“This winter, an emerging La Ni?a is anticipated to influence the upcoming winter patterns, especially our precipitation predictions,” said Jon Gottschalck, chief of the Operational Prediction Branch of the Climate Prediction Center, in a statement. However, a weaker La Ni?a "implies that it would be less likely to result in conventional winter impacts," the CPC added.

The center's forecast covers the months of December, January and February, which is known as meteorological winter.

Snowy winter for the Great Lakes, Northwest?

Notoriously snowy portions of the country could be socked with snow this winter, based on the CPC's precipitation forecast for the U.S. Specifically, wetter-than-average conditions are most likely in the Great Lakes states, the Pacific Northwest and across the northern Rockies.

And while the forecast doesn't specify how much precipitation falls as rain, ice or snow, it's certainly likely that in these cold regions, much of what falls will fall as snow.

How much snow? Some of the nation's (and world's) snowiest spots are in the parts of the country that could see big snows this winter. For example, the Mount Baker ski area in Washington state, in the winter of 1988-89 reported a world record of 95 feet of snow for the entire season.

Lake-effect snow downwind of Lake Erie in New York can be "among the heaviest snowfall in the world," said Weather.com meteorologist Jonathan Erdman, who noted that "a multi-day siege of lake-effect snow in November 2022 buried parts of the Buffalo area with up to 81 inches of snowfall."

'It's still going to be cold this winter'

In the South, meteorologists remind folks that an overall dry, mild climate forecast doesn't mean winter won't make an appearance.

Despite what the long-range forecast says, there will still be cold days and wet periods this winter, said Gary Goggins, a meteorologist with the National Weather Service office in Birmingham, Alabama.

"It's still going to be cold this winter," he said. "There will be days, and periods, when it will be very cold. There will be systems that come through the state bringing cold weather and the possibility of severe weather just like what happens every winter."

What about East Coast snowstorms and blizzards?

The forecast released last week predicts only where above- or below-normal temperatures and above- or below-normal precipitation are most likely.

This winter forecast does not specify how much precipitation will fall as rain, snow or ice, only that more or less is likely overall. Snow forecasts depend upon the strength and track of winter storms, which generally cannot be predicted more than a week in advance, the center has said.

However, Gottschalck said that the storm track for nor'easters along the East Coast might favor more mild air for the big cities of the Northeast and Mid-Atlantic, which could mean more rain than snow there. But he warned that snowstorms are still possible, depending on the specific weather conditions at the time.

Contributing: Marty Roney, Montgomery Advertiser

This article originally appeared on USA TODAY: Winter 2024 forecast hinges on looming La Ni?a